A human body sensor network is a network in which sensor nodes are installed in a human body in a wearable form of putting the sensor nodes on a user or attaching the sensor nodes to the human body or in an implanted form of implanting the sensor nodes in the human body to monitor biomedical signals such as blood clucose contents, blood pressure, oxygen saturation, temperature, electrocardiogram and the like of the user and wirelessly transmit the monitored biomedical signals to a predetermined terminal, and the human body sensor network can be widely applied to a service such as U-health or the like by transmitting the information collected by the sensor nodes to an appropriate place such as a hospital or the like in real-time through a cellular phone or a small-scale base station.
When the sensor node implanted in the human body (hereinafter, referred to as “implant sensor node”) in the human body sensor network monitors biomedical signals or transmits the monitored biomedical signals to the cellular phone or the small-scale base station, it generates heat. The heat generated by the implant sensor node bring a great danger to a person in the long run since it may kill body cells.
Various algorithms have been proposed to control the heat generated by the implant sensor node in the implantable body sensor network to be lower than a predetermined threshold temperature.
An algorithm proposed first as a routing algorithm considering the heat generated by the implant sensor node in the implantable body sensor network is a Thermal-Aware Routing Algorithm (TARA) algorithm. If temperature of the implant sensor node increases to be higher than the threshold temperature, the TARA algorithm controls increase of temperature of the implant sensor node by allowing the implant sensor node, the temperature of which is increased to be higher than the threshold temperature, to stop relaying transmission and reception of data monitored by neighboring sensor nodes.
Meanwhile, a Least Temperature Routing (LTR) algorithm has been proposed as another routing algorithm considering the heat generated by the implant sensor node in a conventional implantable body sensor network. When the biomedical signals monitored by the implant sensor node is transmitted to a destination node, the Least Temperature Routing algorithm selects a neighboring implant sensor node having lowest temperature among implant sensor nodes in the neighborhood of the implant sensor node and transmits the monitored data to the destination node.